Filter Element

ABSTRACT

A filter element ( 1 ) having a filter pot ( 3 ) which delimits a cylindrical interior ( 5 ) and has a bottom part ( 7 ) having a fluid connection ( 11 ), a lid part ( 37 ) opposite the bottom part, a filter medium ( 29 ) adjacent to the inner wall of the filter pot ( 3 ) in the form of a hollow cylindrical body leaving the central region of the interior ( 5 ) free, and having fluid passages ( 31 ) in the wall of the filter pot ( 3 ) surrounding the filter medium ( 29 ), is characterized in that a ring body ( 53 ) which is envisaged as a connecting part between filter pot ( 3 ) and lid part ( 37 ) and has a jacket part ( 55 ) which extends axially along the end section ( 57 ) of the filter pot ( 3 ) and an end part ( 51 ) which extends radially inward and spans the edge of the filter pot ( 3 ) and the edge of the lid part ( 37 ) is provided, and in that, on the end part ( 51 ) of the ring body ( 53 ) and on the lid part ( 37 ), interacting snap connectors ( 59, 61 ) are provided to form a snap connection between end part ( 51 ) and lid part ( 37 ).

The invention relates to a filter element having a filter pot which delineates a circular cylindrical interior with a bottom part which has a fluid port, a cover part opposite the bottom part, a filter medium which adjoins the inside wall of the filter pot in the form of a hollow cylindrical body which leaves the central region of the interior free, and having fluid passages in the wall of the filter pot which encompasses the filter medium.

Filter elements of this type are conventional. For use in assigned filter units these filter elements after opening or removing the housing cover are inserted into a filter housing whose housing bottom has a seat for the fluid port which is located on the bottom part of the filter element and via which the fluid to be filtered enters the inner cavity of the filter element encompassed by the filter medium. For the cleaned fluid which emerges on the outside of the filter pot after flowing through the filter medium, the filter housing, preferably likewise on its bottom, has a fluid outlet.

Since such filter elements must be replaced by an unused filter element after an appropriate operating interval has passed, a design is desired which enables both simple and economical production and also simple handling, that therefore disassembly and installation can be easily done in a time-saving manner.

In this respect the object of the invention is to make available a filter element which meets the aforementioned requirements to a special degree.

This object is achieved according to the invention by a filter element which has the features of claim 1 in its entirety.

In that, as specified in the characterizing part of claim 1, there is a ring body as a connecting part which enables a bond between the cover part and filter pot using a snap connection, the advantage of especially efficient and simple assembly of components of the filter element arises; this enables economical production.

In especially advantageous embodiments the cover part on its periphery is made step-like such that when the snap connection to the ring body has been established, its end part together with the pertinent step on the cover part borders an annular groove which forms a seat for an O-ring with which the cover part is sealed relative to the filter housing which holds the filter pot.

This configuration, due to the double function of the ring body which acts as a connecting element between the cover part and filter pot and at the same time also forms part of the outer seal of the cover part, simplifies production to a particularly high degree.

In filter elements of this type, in the conventional manner at least on that end region of the filter medium which is adjacent to the cover part, there is an adhesive bond, and the cement material can be present as a binder both within the filter medium and can also form a bond to the cover part. In one advantageous embodiment of the invention, with respect to this end-side adhesive bond, the inside diameter of the jacket part of the ring body is chosen to be slightly larger than the outside diameter of the region of the filter pot surrounded by the jacket part. In the end section of the filter pot which is intended for the adhesive bond, between the outside of the filter pot and the inside of the jacket part of the ring body, an annular gap is thus formed which is available for holding the cement material.

With respect to the adhesive bond, the arrangement can also be such that the cover part on its inside facing the interior of the filter pot has at least one groove-like depression for holding cement material which is used to form the adhesive bond in the end region of the filter medium adjacent to the cover part.

Preferably, for this purpose there are two groove-like depressions which run parallel laterally from the central region of the cover part at a distance from one another and which have a dovetail-like cross section so that the respective groove is widened on its base.

The subject matter of the invention is also a filter means which is intended to hold a filter element according to the invention and which has the features of claim 8 in its entirety.

The invention will be detailed below using the drawings.

FIGS. 1 and 2 show a side view and perspective oblique view of one embodiment of the filter element according to the invention;

FIG. 3 shows a longitudinal section of the embodiment of the filter element corresponding to the intersection line III-III from FIG. 1, the filter element being inserted into a filter housing which is shown highly schematically simplified and likewise in a longitudinal section;

FIG. 4 shows an exploded drawing of only the cover part and the ring body which form the components of the embodiment of the filter element, on a larger scale in a perspective oblique view, and

FIG. 5 shows a cutaway view of the region designated as V in FIG. 3 drawn on a still larger scale.

The filter element, which is designated as a whole as 1 in FIGS. 1 and 2, has a filter pot 3 which is made of a plastic material and which borders a circular cylindrical interior 5 for holding the filter medium 29. The interior on the bottom-side end is closed by a bottom part 7 in whose central region, which is referenced to the longitudinal axis 9, there is a fluid port 11. On the latter there is a valve arrangement 13 of conventional design which opens by fluid pressure. A shoulder 15 which encompasses the fluid port 11 and which projects on the bottom part 7 concentrically to the longitudinal axis 9 has a peripheral annular groove 17 in which an O-ring 19 sits. When the filter element 1, as shown in FIG. 3, is inserted into the pertinent filter housing 21 and the insert 15 on the bottom part 7 of the filter element 1 is located in a seat 23 of the bottom 25 of the filter housing 21, the O-ring 19 seals the fluid port 11 and a fluid inlet 27 which is connected to it on the housing bottom 25 relative to the space 27 (FIG. 3) which when the filter element 1 has been inserted into the filter housing 21 is located on the outside of its filter pot 3, and in the filtration process forms the clean side. In other words, the interior 5 to which the fluid to be filtered can be supplied via the fluid port 11 in the filtration process constitutes the dirty side from which the fluid to be filtered passes through the filter medium 29 from the inside to the outside and travels through gap openings 31 (not all numbered in the figures) of the filter pot 3 to the space 27 which forms the clean side. A fluid outlet which is connected to the space 27 in the bottom 25 of the filter housing 21 is designated as 33 in FIG. 3.

As can be taken from FIG. 3, the valve arrangement 13 is located on the bottom part 7 of the filter pot 3 within the centering body 35 which is concentric to the longitudinal axis 9 and through which the fluid which is entering the interior 5 can flow. The filter medium 29 in the form of a hollow cylindrical body which adjoins the inside wall of the filter pot 3 with its outside in its end region which is adjacent to the bottom part 7 encompasses the centering body 35 which defines the inside width of the interior 5. On the end opposite the bottom part 7, the filter pot 3 is sealed by a cover part 37 which has a centering peg 39 which is concentric to the longitudinal axis 9 and which in a manner similar to the bottom-side centering body 35 projects into the interior 5 and similarly centers the filter medium 29 and defines the inside width of the interior 5 in the cover-side region.

As can be seen best in FIGS. 3 and 5, the longitudinal ribs 41 which are made projecting between the slot openings 31 on the outside of the filter pot 3 form spacers which, when the filter element 1 has been inserted into the filter housing 21, keep the outside of the filter pot 3 at a distance from the inside wall of the chamber of the filter housing 21 so that on the outside of the filter pot 3 there is space 27 for the cleaned fluid.

FIG. 3 and especially FIG. 5 show details of the cover part 37. It is stepped on the outer peripheral side, a first step 43 on the outer end having the greatest radial distance from the longitudinal axis 9 and on the cover part 37 defining the same outside diameter as the longitudinal ribs 41 on the filter pot 3. The adjoining second step 45 is offset to the inside by the radial distance. The axial dimension of this second step 45 is matched to the size of an O-ring which sits on this step 45, the radial distance between the first step 43 and the second step 45 being selected such that the O-ring 47 has the slightly compressed shape shown in FIGS. 3 and 5 when it is sealed to the inside wall of the assigned filter housing 21, as is shown in FIGS. 3 and 5. The third step 49 which follows next farther inside is in turn offset radially to the inside and forms a seat for the end part 51 of the ring body 53. This ring body 53 which is made of a plastic material has a hollow cylindrical jacket part 55 which extends along one end section 57 of the filter pot 3, the inside diameter of the jacket part 55 being chosen to be somewhat larger than the outside diameter of the end section 57, so that between them an annular gap 58 is formed, see FIG. 5. The end part 51 of the ring body 53 is drawn radially to the inside so that it overlaps the end edge of the filter pot 3 and sits with the radially inner ring surface on the third step 49 of the cover part 37. As FIGS. 4 and 5 show, on the radially inner ring surface of the end part 51 there is a radially projecting annular rib 59 which snaps into an annular groove 61 in the third step 49 of the cover part 37 with the formation of a snap connection.

As can likewise be best seen from FIG. 5, the ring body 53 on its end facing away from the end part 51 has a bevel 63 which widens the annular gap 58. The annular gap 58 together with the bevel 63 forms a receiving space for the cement material which can form part of the adhesive bond provided in the end section 57. Furthermore, in the side of the cover part 37 facing the filter medium 29 there are groove-like depressions 65 which extend parallel to one another to both sides of the centering peg 39 and have a dovetail-shaped cross section so that widening results on the groove base. These depressions together with the free space 67 which borders the filter medium 69, and with an annular space 69 on the base of the centering peg 39, form receiving spaces for cement material for forming the adhesive bond which is located between the cover part 37 and the filter element 29, the ring body 53 and the filter pot 3. Through openings 71 in the end section 57 of the filter pot 3 can form a passage for cement material between the inside of the filter pot 3 and the annular gap 58.

The snap connection between the ring body 53 and the cover part 37 by means of the annular rib 59 and the groove 61 enables simple and comfortable fixing of the components, for example prior to final attachment and adhesive bonding. Because the end part 51 of the ring body 53 axially borders the second step 45 on the periphery of the cover part 37, the ring body 53 forms not only a connecting element between the cover part 37 and filter pot 3, but at the same time together with the step 45 defines the annular groove 73 for the O-ring 47.

As is shown best in FIG. 2, on the outside of the cover part 37 there are circular sector-like recesses 75 between which there are spoke-like ribs 77 with which the cover part adjoins the corresponding cover 79 of the assigned filter housing 21.

FIG. 3 shows that the closed cover 79 of the filter housing 21, when the filter element 1 has been inserted into it and its fluid port 11 is located in the seat 17 in the bottom 25 of the filter housing 21, with its inside adjoins the ribs 77 on the outside of the cover part 37. The filter element 1 is thus fixed securely in position within the filter housing 21. 

1. A filter element (1) having a filter pot (3) which delineates a circular cylindrical interior (5) with a bottom part (7) which has a fluid port (11), a cover part (37) opposite the bottom part, a filter medium (29) which adjoins the inside wall of the filter pot (3) in the form of a hollow cylindrical body which leaves the central region of the interior (5) free, and having fluid passages (31) in the wall of the filter pot (3) which encompasses the filter medium (29), characterized in that a ring body (53) which is provided as the connecting part between the filter pot (3) and the cover part (37) is provided with a jacket part (55) which extends axially along the end section (57) of the filter pot (3) and with an end part (51) which overlaps the edge of the filter pot (3) and the edge of the cover part (37) and which extends radially to the inside, and that on the end part (51) of the ring body (53) and on the cover part (37) there are catch means (59, 61) which interact with one another to form a snap connection between the end part (51) and the cover part (37).
 2. The filter element according to claim 1, wherein the end part (51) has a radially projecting, annular rib (59) and the cover part (37) has an annular groove (61) which is formed on it on the peripheral side to form a snap connection.
 3. The filter element according to claim 2, wherein the cover part (37) on its periphery is made stepped such that proceeding from the outer end of the cover part (37) a first step (43) whose outside diameter corresponds to the outside diameter of the jacket part (55) of the ring body (53), a second step (45) which is radially farther inside, and a third step (49) which is offset radially still farther to the inside are formed, and wherein the annular groove (61) which is intended for the snap connection to the ring body (53) is machined into this third step (49).
 4. The filter element according to claim 3, wherein the height of the step and the axial dimension of the second step (45) are such that when the snap connection is established to the ring body (53) the latter's end part (51) together with the second step (45) forms an annular groove (73) as a seat for an O-ring (47) in order to seal the cover part (37) relative to the filter housing (21) which holds the filter pot (3).
 5. The filter element according to claim 1, wherein the inside diameter of the jacket part (55) is slightly larger than the outside diameter of the region (57) of the filter pot (3) which is surrounded by the jacket part (55).
 6. The filter element according to of claim 1, wherein the cover part (37) on its inner side facing the interior (5) of the filter pot (3) has at least one groove-like depression (65) for holding cement material for forming an adhesive bond in the end region of the filter medium (29) adjacent to the cover part (37).
 7. The filter element according to claim 6, wherein there are two groove-like depressions (65) which run parallel laterally to the central region of the cover part (37) at a distance from one another and which have a dovetail-like cross section to form a widened base of the depressions (65).
 8. A filter means with a filter housing (21) which has an inner housing chamber (27) which extends along a longitudinal axis (9) between the housing bottom (25) and the housing cover (79) and is intended for holding the filter element (1) according to one of claims 1 to 7, on the housing bottom (25) there being a fluid inlet (27) and a fluid outlet (33) and on the fluid inlet (27) of the housing bottom (25) there being a seat (23) for the fluid port (11) which is located on the bottom part (7) of the filter element (1), characterized in that the end of the housing chamber (27) which is situated a distance from the housing bottom (25) is the same distance away from the housing bottom (25) in the axial direction as the outside of the cover part (37) of the filter element (1) which has been inserted into the seat (23) of the housing bottom (25) with its bottom-side fluid port (11) and which is held in the housing chamber (27). 